The present disclosure generally relates to systems and methods of optical computing and, more specifically, the detection of emulsions and microdispersions with an optical computing device.
In the oil and gas industry, the collection and sampling of underground fluids contained in subterranean formations is well known. Samples of formation fluids are collected and analyzed for various purposes, such as to determine the existence, composition and producibility of subterranean hydrocarbon fluid reservoirs. This aspect of the exploration and recovery process can be crucial in developing exploitation strategies and impacts significant financial expenditures and savings.
In a typical sampling procedure, a sampling tool is lowered to a predetermined depth or location within a wellbore on a conveyance, such as a wireline, slickline, coiled tubing, jointed tubing or the like. The sampling tool may include multiple sensors and/or gauges used to monitor and detect various parameters of the formation fluid. For instance, densitometers are often used to obtain mass and volume flow measurements, and fluid concentration measurements of formation fluids. Moreover, optical computing devices are sometimes used to detect concentrations of particular analytes or chemical compounds present within the formation fluids.
When the sampling tool reaches the desired depth, the sampling tool may be activated to pump or circulate formation fluid through the sampling tool so that the sensors/gauges can monitor the incoming fluids and “sample” the circulating fluid. While monitoring the formation fluids, however, the state of the formation fluids may change into an emulsive state due to, for example, fluid pumping parameters through the sampling tool, downhole environmental conditions (e.g., temperature, pressure, etc.), or a combination of both. As used herein the term “emulsive state” refers to the phase or state of a fluid, such as a formation fluid, and whether said fluid has formed an emulsion, a macroemulsion, a microemulsion, a dispersion, a microdispersion, a colloid, a stable micelle solution, or any combination thereof.
When a formation fluid forms an emulsion or microdispersion, for example, it can be quite difficult to accurately measure the properties or characteristics of the formation fluid, such as the concentration of a particular hydrocarbon present therein. In order to properly measure the properties of the formation fluid, the emulsion or microdispersion must first be broken, which can be done by adding heat, various chemicals, or slow stirring agents, which can take months and even years. Accordingly, for fluid sampling and testing purposes, it may prove advantageous to know when an emulsion is present downhole within a formation fluid being analyzed.